A first conventional piping leakage detecting apparatus is described with reference to FIG. 7.
In gas supply equipment shown in FIG. 7, reference numeral 151 denotes a gas container, 152 a pressure regulator, 153 a feed valve, 154 a gas meter, 156 a gas pipeline, 157 an implement valve, and 158 a gas implement. To inspect the presence or absence of gas leakage of this gas supply equipment, a pressure gauge 159 such as, for example, a manometer is connected to the pipeline 156, and the feed valve 153 and implement plugs 157 are closed with the pipeline 156 filled with gas. Then, it is checked whether or not the gas pressure in the pipeline 156 drops. If any pressure drop is not detected, it is judged that the pipeline 156 is free from gas leakage.
A second conventional piping leakage detecting apparatus is described with reference to FIG. 8.
FIG. 8 depicts a piping leakage detecting apparatus as disclosed in Japanese Patent Publication (examined) No. 2-42185. Reference numeral 156 denotes a pipeline, 160 a gas meter for outputting a flow rate signal depending on the passing gas flow, 161 an inspecting circuit for outputting a notice signal in response to the flow rate signal from the gas meter 160, and 162 an alarm for providing a notification according to the notice signal from the inspecting circuit 161. To detect leakage in the gas supply equipment, the inspecting circuit 161 transmits a flow rate signal below the minimum flow rate of the gas implement. If the flow rate signal is present for a specific period, for example, more than 30 days, it is judged that the leakage is present, and a notice signal is issued.
Next, a third conventional piping leakage detecting apparatus is described with reference to FIG. 9.
FIG. 9 depicts a piping leakage detecting apparatus as disclosed in, for example, Japanese Laid-open Patent Publication (unexamined) No. 4-93739. In this figure, reference numeral 156 denotes a pipeline, 163 a pressure sensor provided in the pipeline 156, and 164 a counting means. It is judged that gas leakage is present in this gas supply equipment when the pressure sensor 163 detects the gas pressure repeatedly within a predetermined period, and the counting means 164 counts that the number of the pressure over a predetermined pressure does not exceed a predetermined number of times, as being warmed by the fresh air during a non-use period of gas.
In the constitution of the conventional apparatus shown in FIG. 7, however, to inspect the gas leakage, an inspector must go to the location of the gas supply equipment and inspect it by stopping the use of gas. If the user of gas is a general household and the house is empty in the daytime, it is difficult to adjust the time schedule for inspection.
In the constitution of the conventional apparatus shown in FIG. 8, it takes about 30 days to detect leakage, and early discovery of gas leakage is impossible.
In the constitution of the conventional apparatus shown in FIG. 9, if the gas non-use time is as short as several minutes, the counting value is small, and gas leakage cannot be inspected.
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide a piping leakage detecting apparatus capable of inspecting gas leakage within a short period of time without requiring an inspector.
Another objective of the present invention is to provide a piping leakage detecting apparatus capable of detecting an accidental massive release of gas due to breakage of a pipeline by earthquake, collision, fire or the like, in addition to detection of gas leakage due to corrosion of gas piping, a crack in rubber piping, or the like.